The titanium screw, and the crown is nothing, these 2 combined is a small part of implant process. Quite often, you have a cavity in the bone due to tooth extraction. The hole must be filled with other people bone, and the new bone has to grow/live in your cavity, eventually grow together with your bone. The screw will be into the new bone, not your bone. The process to developing the new bone is called bone grafting, it can fail easily, that's why the implant is expensive, the screw and crown is nothing. I do not want to gross you out, the bone is from the dead people.